1. The Johns Hopkins University School of Medicine will cooperate in collaborative clinical trials decided on by the principal investigators and the NICHD staff members. This institution has adequate resources including patients with high risk pregnancies, professional staffing, multidisciplinary teams in other specialties, a level III neonatal intensive care unit, antenatal testing facilities, and laboratory facilities. The unit also has demonstrated excellence in maintaining medical records of high quality and collection of data. There is a firm institutional and departmental commitment to support this cooperative study. 2. The proposed protocol is a randomized prospective placebo-controlled trial of the use of terbutaline in patients with preterm premature rupture of membranes without labor between 23-32 weeks of gestation. Patients with evidence of intrauterine infection will be excluded as will patients with vaginal bleeding and any medical diseases contra-indicating the use of terbutaline. Patients will then be randomly assigned according to a table of random numbers to receive terbutaline or an identical appearing placebo and both groups of patients will be followed with excectant management. This will consist of bed rest in the hospital, daily white blood cell counts with differentials and antepartum fetal monitoring with non-stress tests and ultrasound examinations. Patients will be delivered with either maternal or fetal infection or fetal distress. The drug and placebo will be continued until thirty-six weeks if the patient continues to do well until then. Outcome variables to be measured and compared between the two groups include: incidence of maternal and neonatal infection, number of days of prolongation of gestation, gestational age at delivery, birth weight, Apgar scores, incidence of respiratory distress syndrome, other complications, and neonatal survival.